We are conducting a randomized, double blind placebo controlled study of surgery with or without raloxifene, EvistaTM for the treatment of pain from endometriosis. This study evaluates whether a selective estrogen receptor modulator, raloxifene, could prevent the regrowth of endometriosis and return of pain in women with pelvic pain from endometriosis. At the first study surgery, all women have laser excision of endometriosis during a laparoscopy. Those with biopsy proven disease are randomized to study treatment. Throughout the study women monitor the presence and intensity of various types of pelvic pain, their menstrual cycle, and other symptoms. Possible effects of raloxifene on the menstrual cycle, lipids, bone density, and in altering mood, causing headaches or deep vein thrombosis are monitored. We have accrued 85 women. To date, we have examined the usefulness of MRI in diagnosing endometriosis and correlated histopathology with laparoscopic findings. Our analysis suggests that MRI has limited diagnostic utility in a cohort of women with pelvic pain because it has a low detection rate of biopsy proven endometriosis lesions and is relatively insensitive in determining whether an individual woman has endometriosis. In comparing surgical and histopathologic findings, only about 70% of endometriosis lesions seen at surgery are biopsy proven. In the next year, we will evaluate the utility of serum and urine markers for the diagnosis of endometriosis, the relationship between pre-operative pain and the surgical findings, and the utility of intraoperative Marcaine instilled under the diaphragm in decreasing post-operative pain and nausea. In collaboration with the Endometriosis Association, we analyzed survey responses of almost 4000 women with surgically diagnosed endometriosis for their symptoms and coexisting conditions. Almost all responders had pain (99%), and many reported infertility (41%). In this cohort of women with endometriosis, the rates of self-reported diagnoses of hypothyroidism, fibromyalgia, chronic fatigue syndrome, autoimmune diseases, allergies, and asthma were all significantly greater than the published prevalence in the general U.S. female population.